SHUFELDT. ] OSTEOLOGY OF THE CATHARTIDZ. 769 
M. Blanchard, much resemble each other. Itis evident, therefore, that the whole 
structure of a bird and its corresponding habits may be profoundly modified, and yet 
the sternum may retain a very close resemblance to a common form ; and, on the other 
hand, the sternum may undergo the important changes, while the general organiza- 
tion and habits are but little altered. 
To prove that true affinities indicated by the sternum are also in most cases ex- 
hibited in external characters, it is only necessary to refer to the paper above quoted, 
in which the relation of the Hummers to the Swifts, and the sepdration of the Horn- 
bills, the Rollers, the Musophagide, and the Parrots, from the Passeres, were pointed 
out from the consideration of such characters alone. In that paper, however, I made 
two important errors, namely, putting the Todies with the Passeres (from the de- 
scriptions given of their habits) and including the Swallows among the Swifts. The 
character of the sternum is undoubtedly of great importance in finally settling such 
points as these. 
I also at that time included the Psittact among the Scansores; but I am now quite 
convinced that they deserve to rank as a primary division of the class of Birds, a 
rank to which the great peculiarity of the sternum, the large brain-cavity, and highly 
organized cranium fully entitle them. ; 
With regard to M. Blanchard’s determination of affinities from the body of the 
sternum only, without its appendages, I must remark that it often leads to erroneous 
results. For example, he says that the sterna of Merops and Tamatia do not differ 
enough to deserve a separate description, and he includes Megalema with Tamatia in 
one section as having the same form of sternum. He notices some differences in the 
Picide, but remarks on their resemblance to Megalema and to the Toucans. 
Now in all these points an examination of the entire sternum, with the furcula, 
coracoids, and clavicles attached, leads me to very different results. * * * These 
remarks are made in no spirit of depreciation of this very interesting and valuable 
work, but for the purpose of showing that isolated characters may lead to erroneous 
conclusions from whatever part of the organism they are chosen, and that in this 
respect osteological have no positive superiority over external characters. M. Blanch- 
ard tells us, in the introduction to this first instalment ef his work, that he proposes 
to examine successively each separate part of the bird’s skeleton. His future re- 
searches may therefore seriously modify the conclusions he has hitherto arrived at. 
I cannot but think, however, that he would have produced a more satisfactory 
work if he had based it upon the comparison of the entire sternum, with its ap- 
pendages attached, and also on the cranium, these two parts being of the greatest 
importance in classification. 
It has been well observed by Professor Owen that those parts of an animal which 
have the least immediate connection with its habits and economy are exactly those 
which best exhibit deep-seated and obscure affinities. The wings, the feet, and the 
beak in birds may undergo the most extraordinary modifications in the same group 
in accordance with differences of habits and of external conditions, while at the same 
time such apparently insignificant characters as thé general coloring, the texture of 
the plumage, the scaling of the tarsi, or the color and texture of the eggs remain 
constant and reveal the true relations of the species, Thus it is that the form of the 
sternum is of such importance, since it has no immediate dependence on external 
form and habits. The Sparrow, the Flycatcher, the Wren, and the Sunbird all have 
one characteristic form of sternum, while between those of the Swallow and the 
Swift there is the greatest diversity. 
It is evident, also, that the modifications of form immediately dependent on habits 
and external conditions are generally to be seen in the skin even better than in the 
skeleton of a bird. ‘These are principally changes of form, size, and proportion in the 
bill, feet, and the wings, which are excellent characters for distinguishing genera and 
even families; while for determining the true affinities of isolated groups we must 
have recourse to those characters which, having no direct dependence on habits, &c., 
are often persistent in a remarkable degree. Of these, no doubt, the sternum is of the 
highest value; but there are many others of almost equal importance. * * * Now 
that true principles of classification are becoming so much better understood, we may, 
I think, hope that the chaos which has so long existed in ornithology will soon give 
way to a truly natural system which must obtain general acceptance.—(Remarks on 
the Value of Osteological Characters in the Classification of Birds, by Alfred R. Wal- 
lace, Ibis, Lond., 1864, pp. 36-42.) 
In some birds the coracoids and consequently the coracoidal grooves 
on the sternum decussate; now such a marked character as this would 
certainly have to be taken into consideration should we lay too great a 
stress upon this bone as a means of differential diagnosis in classifica- 
tion alone; and we might add to Mr. Wallace’s examples such problems 
as how we would treat or dispose of Polyborus tharus and Ardea hero- 
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